JP2004361212A

JP2004361212A - Rotation angle detector

Info

Publication number: JP2004361212A
Application number: JP2003159242A
Authority: JP
Inventors: Koji Oike; 幸司御池; Kiyotaka Sasanouchi; 清孝笹之内; Kiyotaka Uehira; 清孝植平
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2003-06-04
Filing date: 2003-06-04
Publication date: 2004-12-24
Anticipated expiration: 2023-06-04
Also published as: JP4148031B2

Abstract

【課題】自動車の車体制御システムなどに用いられる多回転のハンドル回転角度検出装置において、被検回転軸と絶対角度検出用歯車との係合がはずれても、大きな誤差を発生することなく、また少容量メモリの演算回路部でも多回転する回転体の回転角度を高分解能に検出でき、歯車や検出手段の異常検出もできる高性能、高信頼性の回転角度検出装置を提供することを目的とする。
【解決手段】被検回転軸１に順次係合されており、歯数はそれぞれ異なる第１、第２の歯車２，３と、歯車２，３の１回転内の絶対回転角をそれぞれ検出する第１、第２の検出手段７，８とを備え、検出された第１、第２の歯車２，３の絶対回転角の組み合わせに基づいて、被検回転軸１の多回転絶対角を検出する回転検出装置において、前記被検回転軸１と、この被検回転軸に順次係合されている第１、第２の歯車２，３の１つとを係合させる第３の歯車４を備える。
【選択図】図１A multi-rotation steering wheel rotation angle detection device used in a vehicle body control system of an automobile or the like, does not cause a large error even if the rotation shaft to be tested is disengaged from an absolute angle detection gear. It is an object of the present invention to provide a high-performance, highly-reliable rotation angle detection device that can detect the rotation angle of a rotating body that makes multiple rotations with a high resolution even with an arithmetic circuit unit of a small capacity memory and can also detect abnormality of gears and detection means. I do.
Kind Code: A1 A first gear and a second gear having different numbers of teeth, which are sequentially engaged with a rotation shaft to be detected, and an absolute rotation angle within one rotation of the gears are detected. It has first and second detection means 7 and 8, and detects a multi-rotation absolute angle of the rotation shaft 1 to be detected based on the detected combination of the absolute rotation angles of the first and second gears 2 and 3. And a third gear 4 for engaging the rotation shaft 1 to be tested and one of the first and second gears 2 and 3 sequentially engaged with the rotation shaft to be tested. .
[Selection diagram] Fig. 1

Description

【０００１】
【発明の属する技術分野】
本発明は、自動車の車体制御システムなどに用いられる回転角度検出装置に関するものである。
【０００２】
【従来の技術】
従来、アブソリュートエンコーダなどのように多回転する回転体の回転角度を検出する装置として、特許文献１に開示されている回転体における角度測定方法及び装置が存在する。この装置においては、位相差を有する複数の回転体の角度から被検回転角度を検出している。
【０００３】
【特許文献１】
特開昭６３−１１８６１４号公報
【０００４】
【発明が解決しようとする課題】
しかしながら、上述の装置においては、歯車の歯欠け、軸ずれなどにより歯車の係合がはずれた場合、被検回転軸の回転角を誤算出する可能性があり、また被検回転軸の回転角を高分解能化するにあたり大容量のメモリを必要としていた。
【０００５】
本発明はこの課題を解決するためのものであり、被検回転軸と絶対角度検出用歯車との係合がはずれても、大きな誤差を発生することなく、また少容量メモリの演算回路部でも多回転する回転体の回転角度を高分解能に検出でき、歯車や検出手段の異常検出もできる回転角度検出装置を提供することである。
【０００６】
【課題を解決するための手段】
上記目的を達成するために、以下の構成を有するものである。
【０００７】
本発明の請求項１に記載の発明は、特に被検回転軸に順次係合されており、歯数はそれぞれ異なる第１、第２の歯車と、これらの第１、第２の歯車の１回転内の絶対回転角をそれぞれ検出する第１、第２の検出手段とを備え、検出された第１、第２の歯車の絶対回転角の組み合わせに基づいて、被検回転軸の多回転絶対角を検出する回転検出装置において、前記被検回転軸と、この被検回転軸に順次係合されている第１、第２の歯車の１つとを係合させる第３の歯車を備えるという構成を有しており、この発明によれば、簡易な構成で、被検回転軸と係合させている第２の歯車との係合がはずれたり、歯欠けが発生しても大きな誤差を発生することなく多回転する被検回転軸の絶対角度を検出することができる。
【０００８】
本発明の請求項２に記載の発明は、特に、前記被検回転軸に順次係合されている第１、第２の歯車との歯数比を１以上の増速比としたもので、被検回転軸の検出角の高分解能化を図ろうとした時、通常は必要となる、各歯車の絶対回転角の組み合わせを記憶する大容量のメモリを削減できる。
【０００９】
本発明の請求項３に記載の発明は、第３の歯車の前記被検回転軸との歯数比が、順次係合されている前記第１、第２の歯車とのものより大きくし、この第３の歯車の絶対回転角を検出する第３の検出手段を設けたもので、被検回転軸の回転検出範囲を満足させる為、被検回転軸に順次係合されている複数の絶対角算出用歯車と被検回転軸との歯数比に制限が加わるが、前記第３の歯車によりこの歯数比よりも高い増速比に自由に設定可能なため、被検回転軸の高分解能化の設計自由度を高められる。
【００１０】
本発明の請求項４に記載の発明は、被検回転軸と第３の歯車とを係合させる第４の歯車を設けたもので、上記請求項１と同様の作用効果が得られる。
【００１１】
本発明の請求項５に記載の発明は、検出された各歯車の絶対回転角のある一定時間における変動量差を監視する制御部を設けたもので、複数の絶対回転角検出用前記歯車の係合はずれの異常を検出し、警報を発することができる。
【００１２】
本発明の請求項７に記載の発明は、前記歯車群の絶対角により算出された前記被検回転軸の多回転絶対回転角をシリアル信号として送信する演算回路部を設けることにより、絶対回転角検出部の信号を直接メインシステム部に伝えるよりも外来ノイズによる絶対角信号の異常防止や、メインシステムのソフト処理負担の軽減ができるという作用効果が得られる。
【００１３】
【発明の実施の形態】
以下、本発明の実施の形態について、図１から図８を用いて説明する。
【００１４】
（実施の形態１）
図１、図２において、１は外周に歯車がついた被検回転軸、２は被検回転軸１と係合した歯車、３は歯車２と係合した歯車、４は歯車３及び被検回転軸１と係合した歯車である。５は歯車２の中央部に組み込まれている磁石、６は歯車３の中央部に組み込まれている磁石、７は歯車２とともに回転する磁石５の磁界方向を検出する第１の検出手段（異方性磁気検出素子）、８は歯車３とともに回転する磁石６の磁界方向を検出する第２の検出手段（異方性磁気検出素子）である。
前記歯車２は下ケース９に設けられた軸受け１０により位置規制されている。一方、被検回転軸１の歯車の歯数ａ、歯車２の歯数ｂ、歯車３の歯数ｃは、ａ／ｂ＞１、ａ／ｃ＞１、ｂ≠ｃとなるように設定する。図２において、第１の検出手段７は下ケース９に固定された基板１２に実装されており、磁石５の真上に配置されている。第２の検出手段８、歯車３及び磁石６も図２で示されている構造と同じ形態をとっている。
【００１５】
図３において、第１の検出手段７と第２の検出手段８は演算回路部１３に接続されており、これらは回転角度検出装置１４に内蔵されており、この演算回路部１３は車両の姿勢制御等を行うメインシステム部１５とシリアル通信ラインで接続されている。
【００１６】
次に、以上の構成により被検回転軸１の回転角度検出の方法について説明する。
【００１７】
図１において被検回転軸１が回転したとき、その外周にある歯車と係合している歯車２が回転すると同時に、歯車２と係合している歯車３及び被検回転軸１と歯車３に係合している別歯車４も回転する。
【００１８】
歯車２は被検回転軸１に対してａ／ｂ倍の速さで回転し、歯車３は被検回転軸１に対してａ／ｃ倍の速さで回転する。第１の検出手段７は歯車２に組み込まれている磁石５の真下に配置されているため、歯車２が回転すると第１の検出手段７を貫く磁石の方向が変化し、歯車２の回転角度に応じた信号を得ることができる。同様に第２の検出手段８も歯車３の回転角度に応じた信号を得ることができる。
【００１９】
図３に示すように、被検回転軸１の多回転絶対角の算出は、演算回路部１３で第１の検出手段７と第２の検出手段８それぞれの絶対角信号を入力して行われ、その演算結果はシリアル信号としてメインシステム部１５へ定期的に送信される。
【００２０】
図４にて被検回転軸１の多回転絶対角を算出する方法について説明する。歯車２は被検回転軸１の回転に対してａ／ｂ倍の速さで回転し、歯車３は被検回転軸１の回転に対してａ／ｃ倍の速さで回転するが、ｂ≠ｃであるので歯車２と歯車３の位相差はある規則をもって変動する。これは被検回転軸１の多回転絶対角１８が歯車２の絶対角値１６と歯車３の絶対角値１７の組み合わせが回転検出範囲において、１対１に決定されることを意味する。歯車２の歯数ｂと歯車３の歯数ｃの最小公倍数を被検回転軸１の歯車の歯数ａで割った値ｄだけ回転すると、歯車２も歯車３も初期回転位置、すなわち両歯車の絶対角が０°になる位置に戻る。この値ｄが回転検出範囲となる。歯車２の歯欠け、被検回転軸１との軸ずれ等によって被検回転軸１と歯車２との係合がはずれても、別歯車４にて、歯車３、歯車２へ被検回転軸１の回転を伝えることができるので、被検回転軸１の多回転絶対角の算出が継続して行える。
【００２１】
一方、演算回路部１３では、歯車２の絶対角値と歯車３の絶対角値の組み合わせに対して被検回転軸１の多回転絶対角値をテーブルとして持つようにしているが、被検回転軸１の検出回転角度の分解能を上げようとすると、テーブルにもつ角度データの数量を増加させる必要があり、演算回路部１３のメモリ空間が非常に大きなものになり、能力的にも限界が発生する。
【００２２】
そこで、テーブルにもつ角度データの数量を削減する方法を図４にて説明する。歯車２の絶対角値１６と歯車３の絶対角値１７の組み合わせによる、被検回転軸１の絶対角１８の決定は粗くする。この粗い絶対角１８は、歯車２の回転周期１９の初期回転位置からの回転数ｅを決定するのにだけ用いる。すなわち、絶対角１８の分解能は歯車２の回転周期以下の角度に設定すればよい。被検回転軸１の細かい絶対角度は、被検回転軸１よりも高速で回転している歯車２の絶対角１７から演算する。すなわち、被検回転軸１の多回転絶対角は
（３６０［°／回転］＊ｅ［回転］＋（絶対角１７））／（ａ／ｂ）［°］
となる。この場合、被検回転軸１と歯車２の歯数比ａ／ｂを大きくすれば、被検回転軸１の検出角度の分解能を上げることができる。
【００２３】
被検回転軸１の多回転絶対角の分解能を更に向上するには、被検回転軸１と歯車２の歯数比ａ／ｂもしくは、歯車３と被検回転軸１の歯数比ａ／ｃを大きくする必要があるが、歯車２の歯数ｂと歯車３の歯数ｃと被検回転軸１の歯数ａによって回転検出範囲ｄが決定される為歯数ａ、ｂ、ｃの設計自由度に限界がある。
【００２４】
そこで図５に示すように歯数を自由に設定できる別歯車４の中央部に磁石２０を組み込み、この磁石２０の真上に第３の検出手段２１を配置し、別歯車４の絶対角を検出する。詳細構造は、図２で示されているものと同じ形態をとる。
【００２５】
歯車４の歯数をｆとしたとき、ａ／ｆ＞１、ｂ＞ｆ、ｃ＞ｆとなるように設定する。
【００２６】
被検回転軸１の多回転絶対角の算出方法を図６に示す。歯車２の絶対角値２２と歯車３の絶対角値２３の組み合わせにより、被検回転軸１の粗い絶対角２４を決定する。この粗い絶対角２４により、別歯車４の回転周期２５の初期回転位置からの回転数ｇを決定する。被検回転軸１の細かい絶対角度は、被検回転軸１よりも高速で回転している別歯車４の絶対角２６から算出する。すなわち、被検回転軸１の多回転絶対角は
（３６０［°／回転］＊ｇ［回転］＋（絶対角２６））／（ａ／ｆ）［°］
となり、前記歯車２と前記歯車３で求めた被検回転軸１の多回転絶対角よりも高分解能化が図れる。
【００２７】
一方、図１において、歯車２と被検回転軸１及び歯車３との係合はずれが、歯車２、歯車３の歯欠け、軸ずれ等によって発生した場合や第１の検出手段７と第２の検出手段８に異常が発生した場合は、図４に示すような歯車２と歯車３の位相差の規則性がなくなり、被検回転軸１の多回転絶対角の算出を誤まる。そこで、図７に示す異常検出フローにてこの異常を検出する。まず、演算回路部１３で、第１の検出手段７と第２の検出手段８の絶対角信号より、処理２７、処理２８にて歯車２及び歯車３の絶対角のある一定時間における変動量Ｘ，Ｙを算出する。次に、処理２９にて｜Ｘ−Ｙ｜と定数Ａとの大小を判定し、大きい時には処理３０にてメインシステム部１５にこの異常を知らせる信号を、図３に示すシリアル通信にのせて、被検回転軸１の誤った絶対角値で車体制御されることを防ぐ。
定数Ａは歯車２と歯車３の歯数差及び被検回転軸１の最大回転速度ｈ［°／ｓｅｃ］、変動量Ｘ，Ｙを算出する時間ｔ［ｓｅｃ］により決定する。すなわち
Ａ＝｜ｈ＊（ａ／ｂ−ａ／ｃ）＊ｔ｜
となる。
【００２８】
（実施の形態２）
図８は実施の形態２における回転角度検出装置の構成図である。
【００２９】
図８において、１は外周に歯車がついた被検回転軸、２は被検回転軸１と係合した歯車、３は歯車２と係合した歯車、３１は被検回転軸１と係合した歯車、３２は歯車３１と歯車２に係合した歯車である。５は歯車２の中央部に組み込まれている磁石、６は歯車３の中央部に組み込まれている磁石、７は歯車２とともに回転する磁石５の磁界方向を検出する第１の検出手段（異方性磁気検出素子）、８は歯車３とともに回転する磁石６の磁界方向を検出する第２の検出手段（異方性磁気検出素子）である。歯車２は、図２に示すように下ケース９に設けられた軸受け１０により位置規制されており、歯車３、歯車３１、３２も同様に下ケース９に設けられた軸受けにより位置規制する。
【００３０】
次に、以上の構成により被検回転軸１の回転角度検出の方法について説明する。
【００３１】
図８において被検回転軸１が回転したとき、その外周にある歯と係合している歯車２が回転すると同時に、歯車２と係合している歯車３が回転する。この時、被検回転軸１に係合している歯車３１及びこの歯車３１と歯車２に係合している歯車３２も回転する。
【００３２】
被検回転軸１の多回転絶対角の算出は、実施の形態１で記述したように、歯数の異なる歯車２、歯車３に組み込まれている磁石５、磁石６の磁力の方向を第１の検出手段７と第２の検出手段８を検知することにより行っている。
【００３３】
歯車２の歯欠け、軸ずれ等によって被検回転軸１と歯車２との係合がはずれても、歯車３１と歯車３２にて、歯車２へ被検回転軸１の回転を伝えることができるので、被検回転軸１の多回転絶対角の算出が継続して行える。
【００３４】
【発明の効果】
以上のように本発明によれば、被検回転軸と絶対角度検出用の第１の歯車との係合がはずれても、大きな誤差を発生することなく、また少容量メモリの演算回路部でも多回転する被検回転軸の回転角度を高分解能に検出でき、歯車や検出手段の異常検出もできる高性能、高信頼性、回転角度検出装置を簡易な形態で提供することができる。
【図面の簡単な説明】
【図１】（ａ）（ｂ）は本発明の実施の形態１による回転検出装置の平面図と側面図
【図２】本発明の実施の形態１における図１の１１部分の拡大図
【図３】本発明の実施の形態１による回転角度検出装置のシステム構成図
【図４】本発明の実施の形態１における歯車２と歯車３の絶対角より被検回転軸１の多回転絶対角を算出する原理図
【図５】本発明の実施の形態１による別歯車４の絶対回転角を検出する手段を備えた回転角度検出装置の平面図
【図６】本発明の実施の形態１における歯車２と歯車３及び別歯車４の絶対角より被検回転軸１の多回転絶対角を算出する原理図
【図７】本発明の実施の形態１における歯車の係合はずれの異常を検出するフローチャート
【図８】本発明の実施の形態２による回転検出装置の平面図
【符号の説明】
１被検回転軸
２歯車
３歯車
４歯車
５磁石
６磁石
７第１の検出手段
８第２の検出手段
９下ケース
１０軸受け
１１回転角度検出装置の部分拡大図
１２基板
１３演算回路部
１４回転角度検出装置
１５メインシステム部
１６歯車２の絶対角値
１７歯車３の絶対角値
１８被検回転軸１の多回転絶対角
１９歯車２の回転周期
２０磁石
２１第３の検出手段
２２歯車２の絶対角値
２３歯車３の絶対角値
２４被検回転軸１の粗い絶対角
２５別歯車４の回転周期
２６別歯車４の絶対角
２７処理部
２８処理部
２９処理部
３０処理部
３１歯車
３２歯車[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rotation angle detection device used for a vehicle body control system or the like of an automobile.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as an apparatus for detecting a rotation angle of a rotating body that makes multiple rotations such as an absolute encoder, there is an angle measuring method and apparatus for a rotating body disclosed in Patent Document 1. In this device, a rotation angle to be detected is detected from angles of a plurality of rotating bodies having a phase difference.
[0003]
[Patent Document 1]
JP-A-63-118614
[Problems to be solved by the invention]
However, in the above-described apparatus, when the gear is disengaged due to lack of teeth of the gear, misalignment of the gear, etc., the rotation angle of the rotation shaft to be measured may be erroneously calculated. In order to achieve high resolution, a large capacity memory was required.
[0005]
The present invention has been made to solve this problem, and does not cause a large error even if the rotation shaft to be tested is disengaged from the absolute angle detection gear, and can be used in an arithmetic circuit of a small capacity memory. An object of the present invention is to provide a rotation angle detection device that can detect the rotation angle of a rotating body that makes multiple rotations with high resolution and can also detect abnormality of gears and detection means.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has the following configuration.
[0007]
The invention according to claim 1 of the present invention particularly includes first and second gears which are sequentially engaged with the rotation shaft to be tested and have different numbers of teeth, respectively, and one of the first and second gears. First and second detection means for detecting absolute rotation angles in rotation, respectively, and based on a combination of the detected absolute rotation angles of the first and second gears, a multi-rotation absolute rotation of the rotation shaft to be measured is provided. In a rotation detecting device for detecting an angle, a configuration is provided that includes a third gear that engages the rotation shaft to be tested and one of first and second gears that are sequentially engaged with the rotation shaft to be tested. According to the present invention, with a simple configuration, a large error is generated even if the engagement with the second gear engaged with the rotating shaft to be tested is disengaged or the tooth is missing. It is possible to detect the absolute angle of the rotation axis of the test object that makes multiple rotations without performing.
[0008]
The invention according to claim 2 of the present invention is particularly configured such that the gear ratio between the first and second gears sequentially engaged with the rotation shaft to be tested is 1 or more, When an attempt is made to increase the resolution of the detection angle of the rotation axis to be tested, a large-capacity memory for storing a combination of absolute rotation angles of the gears, which is normally required, can be reduced.
[0009]
In the invention according to claim 3 of the present invention, the ratio of the number of teeth of the third gear to the rotation shaft to be measured is larger than that of the first gear and the second gear that are sequentially engaged, A third detecting means for detecting the absolute rotation angle of the third gear is provided. In order to satisfy the rotation detection range of the rotation shaft to be tested, a plurality of absolute engagements sequentially engaged with the rotation shaft to be tested are provided. Although the ratio of the number of teeth between the angle calculation gear and the rotation shaft to be tested is restricted, the speed increase ratio higher than this gear ratio can be freely set by the third gear. The degree of freedom in designing resolution can be increased.
[0010]
According to a fourth aspect of the present invention, a fourth gear for engaging the rotary shaft to be tested with the third gear is provided, and the same operation and effects as those of the first aspect are obtained.
[0011]
The invention according to claim 5 of the present invention is provided with a control unit for monitoring the difference in the amount of absolute rotation angle of each gear detected over a certain period of time. An abnormality of the disengagement can be detected and an alarm can be issued.
[0012]
The invention according to claim 7 of the present invention provides an arithmetic circuit unit that transmits a multi-rotation absolute rotation angle of the rotation shaft to be measured calculated from an absolute angle of the gear group as a serial signal, thereby providing an absolute rotation angle. As compared with the case where the signal of the detection unit is directly transmitted to the main system unit, an effect of preventing an abnormality of an absolute angle signal due to external noise and reducing a software processing load on the main system can be obtained.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
[0014]
(Embodiment 1)
1 and 2, reference numeral 1 denotes a rotating shaft to be tested having a gear on the outer periphery, 2 denotes a gear engaged with the rotating shaft 1 to be tested, 3 denotes a gear engaged with a gear 2, 4 denotes a gear 3 and a This is a gear engaged with the rotating shaft 1. 5 is a magnet incorporated in the central part of the gear 2, 6 is a magnet incorporated in the central part of the gear 3, and 7 is a first detecting means (different type) for detecting the magnetic field direction of the magnet 5 rotating with the gear 2. Reference numeral 8 denotes second detection means (anisotropic magnetic detection element) for detecting the magnetic field direction of the magnet 6 rotating together with the gear 3.
The position of the gear 2 is regulated by a bearing 10 provided in a lower case 9. On the other hand, the number of teeth a of the gear of the rotary shaft 1 to be tested, the number of teeth b of the gear 2, and the number of teeth c of the gear 3 are set so that a / b> 1, a / c> 1, and b ≠ c. . In FIG. 2, the first detection means 7 is mounted on a substrate 12 fixed to the lower case 9, and is disposed right above the magnet 5. The second detecting means 8, the gear 3, and the magnet 6 also have the same configuration as the structure shown in FIG.
[0015]
In FIG. 3, the first detecting means 7 and the second detecting means 8 are connected to an arithmetic circuit unit 13 which is built in a rotation angle detecting device 14, and the arithmetic circuit unit 13 It is connected to a main system unit 15 that performs control and the like by a serial communication line.
[0016]
Next, a description will be given of a method of detecting the rotation angle of the rotating shaft 1 to be tested with the above configuration.
[0017]
In FIG. 1, when the rotating shaft 1 to be tested rotates, the gear 2 engaged with the gear on the outer periphery thereof rotates, and at the same time, the gear 3 engaged with the gear 2 and the rotating shaft 1 and the gear 3 to be tested. The other gear 4 which is engaged with also rotates.
[0018]
The gear 2 rotates at a / b times the speed of the rotating shaft 1 to be tested, and the gear 3 rotates at a / c times the speed of the rotating shaft 1 to be tested. Since the first detecting means 7 is disposed immediately below the magnet 5 incorporated in the gear 2, when the gear 2 rotates, the direction of the magnet passing through the first detecting means 7 changes, and the rotation angle of the gear 2 changes. Can be obtained. Similarly, the second detecting means 8 can obtain a signal corresponding to the rotation angle of the gear 3.
[0019]
As shown in FIG. 3, the calculation of the multi-rotation absolute angle of the rotation shaft 1 to be tested is performed by inputting the absolute angle signals of the first detection means 7 and the second detection means 8 by the arithmetic circuit unit 13. The calculation result is periodically transmitted to the main system unit 15 as a serial signal.
[0020]
A method for calculating the multiple rotation absolute angle of the rotation shaft 1 to be tested will be described with reference to FIG. The gear 2 rotates at a / b times the rotation of the rotation shaft 1 to be tested, and the gear 3 rotates at a / c times the rotation of the rotation shaft 1 to be tested. Since ≠ c, the phase difference between the gear 2 and the gear 3 fluctuates according to a certain rule. This means that the combination of the absolute angle value 16 of the gear 2 and the absolute angle value 17 of the gear 3 is determined on a one-to-one basis in the rotation detection range. When the least common multiple of the number of teeth b of the gear 2 and the number of teeth c of the gear 3 is divided by the number d of teeth of the gear of the rotating shaft 1 to be tested, the gear 2 and the gear 3 are both rotated at an initial rotational position. Returns to the position where the absolute angle becomes 0 °. This value d is the rotation detection range. Even if the engagement between the test rotation shaft 1 and the gear 2 is disengaged due to the lack of teeth of the gear 2 or the misalignment with the test rotation shaft 1, the rotation of the test rotation shaft is changed to the gear 3 and the gear 2 by another gear 4. 1 can be transmitted, so that the multi-rotation absolute angle of the rotation shaft 1 to be measured can be continuously calculated.
[0021]
On the other hand, the arithmetic circuit unit 13 has a multi-rotation absolute angle value of the rotary shaft 1 to be tested as a table for the combination of the absolute angle value of the gear 2 and the absolute angle value of the gear 3. In order to increase the resolution of the detected rotation angle of the axis 1, it is necessary to increase the number of angle data stored in the table, and the memory space of the arithmetic circuit unit 13 becomes very large, and there is a limit in performance. I do.
[0022]
Therefore, a method for reducing the quantity of angle data in the table will be described with reference to FIG. The determination of the absolute angle 18 of the rotary shaft 1 to be tested based on the combination of the absolute angle value 16 of the gear 2 and the absolute angle value 17 of the gear 3 is made coarse. The coarse absolute angle 18 is used only for determining the number of rotations e from the initial rotation position of the rotation period 19 of the gear 2. That is, the resolution of the absolute angle 18 may be set to an angle equal to or less than the rotation cycle of the gear 2. The fine absolute angle of the test rotary shaft 1 is calculated from the absolute angle 17 of the gear 2 rotating at a higher speed than the test rotary shaft 1. That is, the multi-rotation absolute angle of the rotation axis 1 to be measured is (360 [° / rotation] * e [rotation] + (absolute angle 17)) / (a / b) [°].
It becomes. In this case, if the ratio a / b of the number of teeth between the test rotary shaft 1 and the gear 2 is increased, the resolution of the detection angle of the test rotary shaft 1 can be increased.
[0023]
In order to further improve the resolution of the absolute rotation angle of the rotating shaft 1 to be tested, the ratio of the number of teeth a / b between the rotating shaft 1 to be tested and the gear 2 or the ratio a / b of the number of teeth between the gear 3 and the rotating shaft 1 to be tested. Although it is necessary to increase c, the rotation detection range d is determined by the number of teeth b of the gear 2, the number of teeth c of the gear 3, and the number of teeth a of the rotary shaft 1 to be tested. There is a limit in design freedom.
[0024]
Therefore, as shown in FIG. 5, a magnet 20 is incorporated in the center of the separate gear 4 in which the number of teeth can be freely set, and the third detecting means 21 is arranged directly above the magnet 20, and the absolute angle of the separate gear 4 is determined. To detect. The detailed structure takes the same form as that shown in FIG.
[0025]
When the number of teeth of the gear 4 is f, a / f> 1, b> f, and c> f are set.
[0026]
FIG. 6 shows a method for calculating the multiple rotation absolute angles of the rotation shaft 1 to be tested. Based on the combination of the absolute angle value 22 of the gear 2 and the absolute angle value 23 of the gear 3, a coarse absolute angle 24 of the rotary shaft 1 is determined. Based on the coarse absolute angle 24, the number of rotations g from the initial rotation position of the rotation period 25 of the separate gear 4 is determined. The fine absolute angle of the rotary shaft 1 is calculated from the absolute angle 26 of the other gear 4 rotating at a higher speed than the rotary shaft 1. That is, the multi-rotation absolute angle of the rotation axis 1 to be measured is (360 [° / rotation] * g [rotation] + (absolute angle 26)) / (a / f) [°].
Thus, a higher resolution can be achieved than the multi-rotation absolute angle of the rotation shaft 1 to be measured obtained by the gear 2 and the gear 3.
[0027]
On the other hand, in FIG. 1, when the gear 2 is disengaged from the rotation shaft 1 and the gear 3 due to lack of teeth of the gear 2 and the gear 3, the shaft misalignment, or the like, the first detection unit 7 and the second When the abnormality occurs in the detecting means 8, the regularity of the phase difference between the gear 2 and the gear 3 as shown in FIG. 4 is lost, and the calculation of the multi-rotation absolute angle of the rotation shaft 1 to be measured is erroneous. Therefore, this abnormality is detected by the abnormality detection flow shown in FIG. First, the arithmetic circuit unit 13 calculates the variation X in the absolute angle of the gear 2 and the gear 3 in a certain period of time in processing 27 and processing 28 based on the absolute angle signals of the first detecting means 7 and the second detecting means 8. , Y are calculated. Next, in step 29, the magnitude of | X−Y | and the constant A is determined. If the value is larger, a signal notifying the abnormality to the main system unit 15 is sent in step 30 to the serial communication shown in FIG. The vehicle body is prevented from being controlled by an erroneous absolute angle value of the rotary shaft 1 to be tested.
The constant A is determined based on the difference in the number of teeth between the gear 2 and the gear 3, the maximum rotation speed h [° / sec] of the rotary shaft 1 to be tested, and the time t [sec] for calculating the fluctuation amounts X and Y. That is, A = | h * (a / ba-c) * t |
It becomes.
[0028]
(Embodiment 2)
FIG. 8 is a configuration diagram of a rotation angle detection device according to the second embodiment.
[0029]
In FIG. 8, reference numeral 1 denotes a rotating shaft to be tested having a gear on the outer periphery, 2 denotes a gear engaged with the rotating shaft 1 to be tested, 3 denotes a gear engaged with the gear 2, and 31 denotes a rotating shaft to be tested. Reference numeral 32 denotes a gear engaged with the gear 31 and the gear 2. 5 is a magnet incorporated in the central part of the gear 2, 6 is a magnet incorporated in the central part of the gear 3, and 7 is a first detecting means (different type) for detecting the magnetic field direction of the magnet 5 rotating with the gear 2. Reference numeral 8 denotes second detection means (anisotropic magnetic detection element) for detecting the magnetic field direction of the magnet 6 rotating together with the gear 3. The position of the gear 2 is regulated by a bearing 10 provided on the lower case 9 as shown in FIG. 2, and the positions of the gears 3 and the gears 31 and 32 are similarly regulated by bearings provided on the lower case 9.
[0030]
Next, a description will be given of a method of detecting the rotation angle of the rotating shaft 1 to be tested with the above configuration.
[0031]
In FIG. 8, when the rotation shaft 1 to be tested rotates, the gear 2 engaged with the teeth on the outer periphery rotates, and at the same time, the gear 3 engaged with the gear 2 rotates. At this time, the gear 31 engaged with the test rotary shaft 1 and the gear 32 engaged with the gear 31 and the gear 2 also rotate.
[0032]
As described in the first embodiment, the multi-rotation absolute angle of the rotation shaft 1 to be measured is determined by first determining the direction of the magnetic force of the magnets 5 and 6 incorporated in the gears 2 and 3 having different numbers of teeth. The detection is performed by detecting the detection means 7 and the second detection means 8.
[0033]
Even if the rotation of the test rotary shaft 1 and the gear 2 are disengaged due to the lack of teeth of the gear 2, the axial deviation, etc., the rotation of the test rotary shaft 1 can be transmitted to the gear 2 by the gears 31 and 32. Therefore, the multi-rotation absolute angle of the rotation shaft 1 to be measured can be continuously calculated.
[0034]
【The invention's effect】
As described above, according to the present invention, even when the rotation shaft to be tested and the first gear for detecting the absolute angle are disengaged, a large error does not occur and the arithmetic circuit of the small capacity memory can be used. It is possible to provide a high-performance, high-reliability, rotation angle detection device capable of detecting the rotation angle of a multi-rotation rotating shaft with high resolution and detecting abnormality of gears and detection means in a simple form.
[Brief description of the drawings]
1A and 1B are a plan view and a side view of a rotation detecting device according to a first embodiment of the present invention. FIG. 2 is an enlarged view of a portion 11 in FIG. 1 according to the first embodiment of the present invention. 3 is a system configuration diagram of the rotation angle detecting device according to the first embodiment of the present invention. FIG. 4 is a diagram showing a multi-rotation absolute angle of the rotary shaft 1 to be detected based on the absolute angles of the gears 2 and 3 in the first embodiment of the present invention. FIG. 5 is a plan view of a rotation angle detecting device including means for detecting an absolute rotation angle of another gear 4 according to the first embodiment of the present invention. FIG. 6 is a gear diagram according to the first embodiment of the present invention. FIG. 7 is a principle diagram for calculating a multi-rotation absolute angle of the rotary shaft 1 to be detected from the absolute angles of the gear 2, the gear 3 and the separate gear 4. FIG. 7 is a flowchart for detecting an abnormality of gear disengagement according to the first embodiment of the present invention. FIG. 8 is a plan view of a rotation detecting device according to a second embodiment of the present invention. ]
REFERENCE SIGNS LIST 1 rotating shaft 2 to be tested 2 gear 3 gear 4 gear 5 magnet 6 magnet 7 first detecting means 8 second detecting means 9 lower case 10 bearing 11 partial enlarged view of rotation angle detection device 12 substrate 13 arithmetic circuit unit 14 rotation angle Detecting device 15 Main system unit 16 Absolute angle value 17 of gear 2 Absolute angle value 18 of gear 3 Multi-rotation absolute angle 19 of rotating shaft 1 to be tested 19 Rotation cycle 20 of gear 2 Magnet 21 Third detecting means 22 Absolute value of gear 2 Angle value 23 Absolute angle value of the gear 3 24 Coarse absolute angle 25 of the rotating shaft 1 to be tested 25 Rotation period 26 of the other gear 4 Absolute angle 27 of the other gear 4 Processing unit 28 Processing unit 29 Processing unit 30 Processing unit 31 Gear 32 Gear

Claims

First and second gears that are sequentially engaged with the rotation shaft to be tested and have different numbers of teeth, and first and second gears that detect the absolute rotation angles within one rotation of the first and second gears, respectively. A rotation detecting device for detecting a multi-rotation absolute angle of the rotation shaft to be detected based on a combination of the detected absolute rotation angles of the first and second gears. And a third gear that engages one of the first and second gears sequentially engaged with the rotation shaft to be tested.

The rotation angle detection device according to claim 1, wherein the first and second gears have a gear ratio of 1 or more with respect to the rotation shaft to be tested.

The gear ratio of the third gear to the rotating shaft to be tested is greater than that of the first and second gears, and a third detection for detecting the absolute rotation angle of the third gear is performed. The rotation angle detecting device according to claim 1, further comprising a unit.

A rotation angle detection device comprising: a fourth gear that engages a rotation shaft to be tested with a third gear.

The rotation angle detection device according to any one of claims 2 to 4, further comprising: a control unit configured to monitor a variation amount of an absolute rotation angle of each gear sequentially engaged with the rotation shaft to be tested in a predetermined time. .

The rotation angle detection device according to claim 5, wherein the detection means is an anisotropic magnetic detection element.

7. The rotation angle detection device according to claim 6, further comprising an arithmetic circuit unit that transmits, as a serial signal, an absolute rotation angle of the rotation shaft to be measured, which is calculated based on an absolute angle of the gear group.